According to a recent sociological study, cohabitation has a notably deleterious impact on one particular group: kids. “As marriage becomes less likely to anchor the adult life course across the globe, growing numbers of children may be thrown into increasingly turbulent family waters,” writes Bradford Wilcox in Foreign Affairs.

The main study included the United States and 16 European countries. “We were looking at the odds that kids who were born to married or cohabitating parents will still be with their parents when they turn 12,” says Wilcox. “Then we had a sample of more than 60 countries across the globe. When you look internationally at trends, what you see is that there are a number of countries in Sub-Saharan Africa, such as South Africa, and Latin America, like Colombia, that now have a substantial share of kids being born to cohabiting couples. So the question is: How is cohabitation affecting family stability in those other parts of the world, outside the United States and Europe?”

Wilcox spoke recently with CT about the answers they uncovered.

From your perspective, what are the most striking or surprising results from the study?

In the vast majority of countries that we looked at in Europe, at all education levels, people who are married when they have kids are markedly more stable than people who are cohabiting when they have their kids. Generally speaking, the least educated married families in Europe enjoy more stability than the most educated cohabiting families. That’s not what I would have guessed. I assumed that we’d find some kind of marriage stability premium, but I didn’t realize it would be that pronounced, and that marriage was a more powerful predictor of family stability in Europe than parental education.

In other words, the marriage premium is pretty consistent across Europe. And a lot of academics and journalists and policymakers and ordinary professionals make the mistake of thinking that in Europe, cohabitation and marriage are functional equivalents, but in reality they’re not.

Did you find the same “marriage premium” across the globe?

We looked at changes in cohabitation levels and family stability across the globe and found in general that as cohabitation increased, the odds that kids would be living with two biological parents in a given country decreased over time. That pattern was actually most salient or most dramatic in the initial increase in cohabitation. It was negligible for countries that already experienced more than 20 percent of their births to cohabiting couples. But overall, our report is pretty consistent in finding that for kids, marriage typically provides more stability across Europe and the United States. Moreover, across the globe, marriage as the norm for childbearing is also associated with higher levels of family stability at the societal level.

Your colleague Laurie DeRose, a lead author in this report and a professor of sociology at Georgetown University, claims that the study contradicts three myths about cohabitation and family stability. What are those three myths?

The first myth she writes about is that “cohabitation is less stable just because poorer people are more likely to choose it. In fact, cohabitation is less stable than marriage regardless of the mother’s educational background. In the overwhelming majority of countries, the most educated cohabiting parents still have a far higher rate of break-up than the lowest educated married couples.” So if you’re looking at countries in Europe and the United States, it is striking that marital status is a more powerful predictor of family stability than the education of the parents. It’s contrary to what many professors would expect.

The second myth is that “cohabitation becomes more similar to marriage as it becomes more widespread,” that in places where cohabitation becomes legally and culturally accepted, it will be just as stable as marriage. But that is not the case for children.

The final myth, she writes, “is that where cohabitation has been a long-standing alternative to marriage (scholars writing on Latin America and the Caribbean refer to a ‘dual nuptiality’ system), further growth of the institution will not affect children’s lives.” Again, that’s not the case.

You claim to show that “children have more stable family lives when born within marriage regardless of the mother’s educational background.” Why is it significant that the study controlled for education and socioeconomic status?

It’s important because, at least in the United States and certainly elsewhere, lower income and less education are powerful predictors of family instability. And so we want to make sure that we’re not just confusing cohabitation with economic depravation, because cohabiting families are more common particularly in the United States and United Kingdom among working class and poor citizens.

So in the analysis of Europe and the United States, we controlled for both maternal education and the grandmother’s education, mom’s age at first birth, and then country, since obviously Belgium is different than Italy, which in turn is different than Russia. In our results you find the United States, United Kingdom, Russia, Lithuania, and Estonia all have high levels of family instability. And we’re not exactly sure why. Russia has obviously faced a lot of economic strain in recent years and a lot of political change, and that’s also probably true to some extent for Estonia and for Lithuania.

Did the study analyze or account for same-sex marriages?

There probably are a few same-sex marriages in the data, but not enough for us to conduct any kind of separate analysis of that population.

And did you see any correlations with religious affiliation of any sort—Catholic, Protestant, or other religions?

No, we do not. We didn’t look at the specific case of the role religion plays in family stability in this particular study.

However, generally speaking, families in historically Catholic countries tended to enjoy more family stability than kids or families in historically Protestant regions. Some of the most stable countries for kids were predominantly Catholic ones like Italy, Poland, and Spain. And some of the highest levels of instability were in the United States and United Kingdom. So Anglo countries with Protestant, individualistic traditions had some of the highest rates of instability in the West.

Is there any causal link between a rise in cohabitation in the West and a rise in cohabitation around the globe?

My suspicion is that, particularly in Latin America and in Asia, cohabitation is being driven in part by Western-style individualism. It’s a way of maximizing one’s freedom and flexibility in a relationship and minimizing the commitments. Certainly some of the trends in Latin America and Asia are partly a reflection of Westernizing intellectual and pop cultural trends. In Sub-Saharan Africa, however, it’s hard to know how much of it is Western influence versus complicated migration patterns for men’s employment or some other factor. There’s just a lot going on in Sub-Saharan Africa that might be sui generis to Sub-Saharan Africa.

In 2014 you spoke at a meeting at the United Nations, and then in 2015 you testified before the House Ways and Means Committee about the challenges faced by low-income families around the world. How does this new study, along with past studies, impact our understanding of global poverty and efforts to alleviate that poverty?

Although family structure is not the only thing, of course, that affects kids and their families, family instability does tend to reduce the economic resources available to kids and it does tend to foster poverty. An earlier edition of the World Family Map showed that family instability was linked to an increase in child mortality of at least 20 percent for kids in Latin America, Asia, and Sub-Saharan Africa. So for people who are concerned about things like poverty and child mortality, they should be aware that the increasing fragility of family life and the retreat from marriage—which we see playing out across much of the globe—is one factor contributing to poverty. Marriage is an important source of human and financial capital for kids. Kids who are raised in stable married homes in the developing world are more likely be flourishing, and stable families are also associated with better social and health outcomes.

You work with college students in their 20s who are in a formative stage of adulthood and dealing with decisions about cohabitation. How do your students think about your work and its implications?

I’ve been teaching classes in family sociology for about 14 years, and cohabitation is a topic that comes up regularly, because the assumption is that cohabitation is a good way to prepare for marriage. What most students don’t realize is that if you have a child in a cohabiting relationship, you’re increasing the risk that your child will not experience a stable family, and especially if you break up with that person, it affects your ability to forge a marriage down the road. So my students are aware of those kinds of findings.

And then they also learn, too, (and here I’m indebted to the work of Scott Stanley at the University of Denver) that couples who cohabit prior to a public engagement are more likely to flounder in their marriages. We think that’s because they are more likely to experience sliding into marriage rather that deciding to be together and then getting married. In some ways, cohabitation is sort of like being at McDonald’s compared to having a nice meal at one’s home. Cohabitation is quick, it’s convenient, and it can taste good. But it doesn’t leave the same feeling in your stomach as a good home-prepared meal does, and it’s not as healthy and as enriching for you.

How does this study advance the current conversation around marriage?

On the one hand, the science seems to continue to mount that kids are especially likely to flourish when raised by their own married, biological parents. But we also live in world where people don’t necessarily organize their lives and their kids’ lives around marriage. And I think the challenge is: Can we get the message out that marriage matters to a broader public, especially the public that’s not college educated, because they’re the ones who are most disconnected from this institution today? And can we help people acquire the virtues and the resources they need to forge strong, stable marriages?

If we could have something like the campaigns we’ve had against smoking, we could make a lot of progress on this front. But we haven’t yet generated enough elite consensus on the importance of marriage for 2017 or 2018, for that matter, to get people behind a consensual cultural message around marriage as the best way to start families and keep kids and parents together.

And it’s not just about culture; it’s also about economics. We have to be continually thinking about ways to strengthen the economic foundations of families with public policies and also with private company policies—in terms of wages, hiring, and layoffs and also in terms of flexible work schedules that are family friendly.

You gestured toward the anti-smoking campaign. What would it look like to mount a comparable campaign on the marriage issue?

Having something like a “put the baby carriage after marriage” campaign, done in a winsome way, would be helpful and important. It would also be helpful to have a campaign around rethinking marriage for millennials, saying in so many words—you don’t have to be in some kind of fuddy-duddy, bourgeois reality to get married; you could get married in your mid-20s in Seattle or Park Slope or Los Angeles. Marriage is about commitment. It’s about having someone in your corner when you’re starting a new job. It’s about forging a commitment before you have kids. And those things are not predicated on wearing khaki pants and a Ralph Lauren Polo shirt and having a nine-to-five job. Getting people to see that marriage need not be a kind of uniformly conservative institution would be helpful, too. It’s really just a human institution more than anything else. It’s a way of signaling to yourself, to your partner, and to your community that you’re all in. That’s a really powerful signal to enjoy in a relationship, and it’s transformational for many of us.

So much of the rhetoric of modern marriage revolves around identity and self-fulfillment. In the context of this hypothetical campaign, how would you counteract that rhetoric?

We need to make it very clear that kids who are born and raised by married parents are much more likely to flourish. There’s a kind of intergenerational obligation we have, to really try to have our kids within marriage, to give them the gift of two married parents who are committed to one another and to them for the long term. We are more likely to flourish when we live lives marked by generosity and by deep and abiding ties to other people. And of course those two things are more likely to happen in the married context as compared to other contexts. So it’s calling people to their best selves, trying to basically make the case that this is an opportunity to live a certain set of virtues, like fidelity and loyalty and forbearance.

The power of marriage is really an international one, it’s a cross-cultural one, and it’s a way that communities superintend the process of bringing two people together, helping them build a common life together that’s going to be more grounded and rooted when it comes to having kids and rearing kids.